(CNN) — Medical marijuana might be the most effective complementary or alternative medicine to provide relief of symptoms caused by multiple sclerosis (MS) according to new guidelines from the American Academy of Neurology (AAN) released Monday.

Complementary and alternative medicines (CAM) are nontraditional therapies often used in addition to (and sometimes instead of) doctor recommended treatments.

The guidelines are based on recommendations made by a panel of nine physicians chosen by the AAN who are experts in the field of CAM. They identified and reviewed 291 studies and literature from the last 43 years. Of those, 115 made the cut; most were short, lasting between six and 15 weeks.

“This is the first-ever review, evidence-based recommendation, on the treatment of MS with CAM therapies,” says Dr. Vijayshree Yadav, lead author and clinical director of Oregon Health and Science University’s Multiple Sclerosis Center. “There were 29 different therapies included in the guidelines. Nineteen studies looked at cannabis.”

The new guidelines will help clinicians determine if CAM therapies help reduce specific symptoms and prevent relapse or further disability; make the disease worse or cause serious side effects; or interfere with other MS therapies.

“It looks like there is little evidence for the effectiveness of most CAM therapies to treat MS,”Yadav said. “For most CAM therapies safety is unknown. We also did not find evidence to show (whether) the therapies interact with prescription MS drugs.”

Because so many people are using CAM therapies, more research is still needed, Yadav said.

Multiple sclerosis damages the myelin coating around the nerve fibers in the central nervous system, according to the National MS Society, which in turn interferes with the transmission of nerve signals between the brain, spinal cord and the rest of the body.

Women are more often diagnosed than men, and symptoms generally appear between 20 and 50 years of age. The cause is unknown and there is no cure. But a number of treatments can slow the progression and help manage the often debilitating symptoms.

According to the MS Foundation, symptoms typically include fatigue, spasticity (stiffness and involuntary muscle spasms most often in the legs), weakness, balance problems, numbness, vision loss, bladder and bowel issues, tremors and depression. Symptoms are varied, unpredictable, and no patient gets all of them. Most patients go through episodes or attacks and remissions. Sometimes the damage is permanent.

The researchers found certain forms of medical marijuana – oral cannabis extract and synthetic tetrahydrocannabinol (or THC, the psychoactive ingredient in marijuana ) could help reduce spasticity and pain for up to a year, but were ineffective against tremors. They also found Sativex, an oral cannabinoid spray, helps reduce stiffness and frequent urination but not MS-related tremors. Sativex, currently available in 25 countries to help treat MS, is not sold in the United States.

A few other alternative treatments also showed some benefits.

“For example, ginkgo biloba is used by many patients. The study did not find effectiveness for cognition, but possibly effective for fatigue.” Yadav said. “Similarly, magnetic therapy is probably effective for fatigue but probably ineffective for depression. Reflexology showed some evidence that it might help lessen paresthesia (tingling or numbness or unusual skin sensations).”

Both fish oil and bee sting therapy were also found to be ineffective for MS-related relapses, neurologic disability, fatigue, MRI lesions (MS-related lesions on the brain or spinal cord) and quality of life, according to Yadav.

Still researchers warn most CAM therapies are not FDA regulated, leading to concerns about using CAM and in particular cannabis, which can cause side effects that mirror the diseases’ symptoms like dizziness, thinking and memory problems.

Dr. Robert Fox, a neurologist and MS expert at the Cleveland Clinic, called the guidelines “a very important step forward,” but echoed those concerns.

“There are important safety concerns with cannabinoid therapy including marijuana. These include cognitive side effects and mood disruptions, such as depression,” he noted. “Marijuana remains illegal in many states …

clinicians cannot recommend marijuana in states where it is still illegal.”

According to Fox, up to 80% of people with MS use CAM treatments.

“Patients will often seek CAM therapies for their disease,”says Fox. “That makes it difficult for clinicians to always understand the potential benefits and side effects of the various therapies. These guidelines assimilate a large number of CAM therapies into a single source for clinicians by having a guideline for many CAM therapies all in one place so clinicians are better armed to counsel their patients.”